Conclusion: My second L turned out to be a nightmare. Having lost my battery power on my laptop when I was testing the lens, I preview thru my 30D LCD and found it reasonably sharp. And I bought it, but turned out worst on the iMac monitor. Comments from my fellow friends were that this old lens are not suitable for cropped bodies and need a re-calibration. I certainly hope that after the calibration it could change my views on this lens.
Pros: Fast aperture, Fast focusing, Good weight
Cons: All pictures at all f-stop soft, with or without tripod or flash all SOFT... Since I bought second hand and I use it on cropped bodies; Canon Singapore recommend me to send to their service to re-calibrate this lens. I hope after re-calibration, the lens will be sharp as I do not want a whilte elephant. For now I rate it a 5 only.
Summary: On Feb 22, 2007, Canon announced a "II" version of this lens that will correct the optical performance problems this lens has. The new lens has been completely redesigned, and will require MASSIVE 82mm filters. Yikes! I do not own this lens, as I am now waiting to see if the II version will be more expensive, or if this version will drop below $1000.
Conclusion: This is a nice lens, with a a nice range however it has a tendency have extreme flare and ghosting when it is pointing anywhere near the sun. I used this lens without filters, and with the hood. Sunset photos are practically impossible with this lens. The reality is a lens with this range and an f2.8 Maximum aperture requires too many glass elements, which contribute to the flare.
Pros: Fast, quite sharp, nice range 16-35mm on a full frame.
Conclusion: I bought this lens when it came out for film, and now use it mostly on FF bodies, but have also used it on 1.6x bodies. This lens is better than the 17-35 that came before, but again shows that Canon can't/won't buckle down and produce a truly good wideangle. Some fixed focal lenses from the FD days were decent and competitive, but the offerings in the EF line have been poor.
Pros: Well built, fast, nice range.
Cons: Mediocre optical quality. Doesn't get acceptably sharp until f/11 in the corners; low contrast even at smaller apertures.
Conclusion: Oh, it's really well put together: beautifully weatherproofed, and reassuringly L-series chunky in the hand; it's such a shame that such an expensive lens so spectacularly fails to justify its exorbitant cost. It fails to achieve critical sharpness at any aperture; it fails to control CA; and Canon seems to have failed in its quality control to limit sample variation.
Conclusion: I bought this lens to replace the EF-S 17-85IS f/4-5.6 on my 20D. My expectation was better focusing (yes), sharper images (sometimes) and better low light performance (no way). I think the weight, limited zoom range, and range of image quality (from poor at 2.8 or soft at 35 to decent in other circumstances) just didn't sit well with what I paid for it so I returned it.
Pros: Well built Fast, silent focus
Cons: Very poor pictures at f/2.8 but better from 4 on Softness at 35 Strange lens hood Way too expensive Heavy Limited zoom range
Conclusion: I'd expected greater optical performance from a "L-lens". I've shot a few hundred pictures with a 20D, and almost nothing with it impress me. Going to have a chat with Canon regarding a lens calibration - and hope that's the issue with it. Maybe Canon's quality check department is a one man's army.....
Pros: Fast AF, good WA even on 1.6x dSLR, dynamic colors.
Cons: Poor optical performance, really soft, almost all pictures taken at f/2.8 need USM, compared to a the 100USD kit lens (18-55) and the diff. is barely noticeable. Expected ALOT more from a L-lens costing 13 times more than a 'simple' EF-S kit lens *imo*...
Conclusion: Bought this lens to replace a Sigma 15-30 even though I lost 1mm at the wide end this is more than compensated by it being an f2.8. I do not know why anyone has problems with this lens as I find it to give me excellent results all of the time and honestly would feel as if I were missing a limb if I went to job without it.
Pros: Ultra wide angle at f2.8,balances wellon all my equipment
Conclusion: First off, I have never been a fan of zooms and feel they offer a trade off . . . convenience over quality. This one is no exception to what my experience has taught me over the years. I do not have any ultra wide primes to test it against but I did test it against the EF35mm f1.4L. I'd say the 1.4 was about as sharp AT f1.4 as this zoom was at f2.8! Stop the prime to f 2.8 and it was clearly, to my eye, sharper than the zoom, and significantly so . . .